Composite structures made of thermoplastic resins and particulate materials have been widely described. U.S. Pat. No. 4,153,661 describes a method for making composite sheets comprising particulate distributed in a matrix of polytetrafluoroethylene (PTFE) fibrils. U.S. Pat. Nos. 4,373,519 and 4,565,663 disclose methods for making water-swellable composite sheets having hydrophilic absorptive particles enmeshed in a PTFE matrix. U.S. Pat. No. 4,971,736 describes methods of enmeshing non-swellable particulate in a PTFE matrix and their use as chromatographic articles.
U.S. Pat. No. 5,904,848 describes methods for calendering and sintering an aqueous dispersion of PTFE and controlled pore glass (CPG) into rigid porous sheets of 5 to 200 mils in thickness from which disc membranes are being cut. The membrane porosity is adjusted by using CPG of various pore sizes. Post-silanization treatment of the said disc membranes is required to introduce reactive moieties onto the CPG surface.
U.S. Pat. No. 6,416,716 disclosed methods to prepare tubes which interior surfaces are embedding separation medium particles. For instance a polypropylene tube filled with C-18 particles was heated to embed the separation medium particles into the interior of the tubes due to the melting of the polypropylene. Other embedded devices described in World patent No 00/21658 are prepared by sintering functionalized polystyrenes with polyalkylenes especially polyethylene and polypropylene. The said devices contain at least 10 μmol of reactive functionalities available for synthetic purposes notably peptide syntheses. The porosity of those devices to methanol at ambient temperature and pressure is described as being at least of 0.2 mL/min.
Although the general concepts of embedded devices have been discussed, cylindrical devices prepared by embedding modified-CPG in polyalkylene and the methods pertaining to their utilization in the synthesis of nucleic acids have not been developed thus far.